In daily life, hot water is desired under certain circumstances, for example, when used for consumption, washing faces, and the likes, therefore, people often need to heat up the water by boiling. Generally, people boil the water by using a kettle, which typically provides a function of generating a prompt when the water is boiling.
Under general circumstances, a process in which users boil water using the kettle is as follows: cold water is added to the kettle, a cover of the kettle is put onto the kettle, a switch is turned on, the kettle starts to heat up the water, and the kettle triggers a prompt signal (for example, generating a sound or the like) until the water in the kettle is boiling, thus to notify the users that the water is boiling.